Pre-filled syringes that are filled with a selected dosage of a medication are well known injection devices for administering the medication to a patient. Safety devices for covering a needle of a pre-filled syringe before and after use are also well known. Typically, these devices comprise a needle shield that is either manually moved or moved by the action of a relaxing spring to surround the needle.
A different type of safety device known in the state of the art achieves the object of providing needle safety by arranging the pre-filled syringe movable relative to a body, where the pre-filled syringe is retracted into the body after the injection.
WO 2006/111862 A1 discloses an injection assistance device comprising a body with a needle, grasping means and first elastic return means to dampen limited movement of said grasping means, in at least one of the two directions, respectively distal or proximal, during an injection phase, and to maintain said body in its insertion position and said needle at a constant insertion length during the injection step, when the user increases, respectively releases, a distal pressure on the grasping means. WO 2006/111862 A1 also relates to an injection set comprising an injection device and the said assistance device.
FR 2 799 975 A1 discloses a disposable hypodermic syringe having a safety sleeve with a forward end in which a barrel can slide between an operating position with a needle holder deployed and a safety position with it retracted. The syringe has a telescopic head containing a spring which is released automatically at the end of the pressure stroke to retract the barrel and needle inside the sleeve. Disposable hypodermic syringe comprises a barrel, a needle holder, a plunger and a safety sleeve with a forward end in which the barrel can slide between an operating position with the needle holder deployed and a safety position with it is retracted. The syringe has a telescopic head containing a spring which is released automatically at the end of the pressure stroke to retract the barrel and needle inside the sleeve. Lugs inside the head hold the barrel in its retracted position and prevent re-use.
WO 2010/104779 A1 discloses a pharmaceutical delivery apparatus with an automatic syringe retraction following a manually controlled injection. The apparatus includes a housing, a syringe carriage, a medication-filled syringe held within the carriage, the syringe needle tip being disposed within the housing in a first position and projecting from the housing beyond the housing proximal end for insertion into an injection site in a second position, a manually shiftable plunger, means on the carriage and the housing and the plunger for causing the carriage to advance from the first position to the second position and for injecting medicine from the syringe when the plunger is manually plunged proximally toward the housing, and means on the carriage and the plunger for causing the carriage to retract from the second position to a position at which the needle tip is disposed within the housing when the plunger shifts distally.
EP 1 970 086 A2 discloses an injection device for use with a pre-filled syringe. The device features a track and track follower engagement which facilitates locking a protective needle guard over the tip of the needle at the conclusion of the injection. The device further includes a tamper evidence overcap which, once removed from the device cannot be readily reinstalled. The injection device features a tubular handle which is grasped by the hand and moved towards the injection site to administer the injection. The device is suitable for self-administration of injections.
WO 2007/047200 A1 discloses a pharmaceutical delivery apparatus including a housing, a syringe assembly, and a needle cap. The syringe assembly is plungeable relative to the housing from a first position, at which its needle tip is disposed within the housing, to a second position, at which its needle tip projects from the housing beyond the proximal end for insertion into an injection site. A base of the needle cap is exposed at the housing proximal end to be manually grippable for cap removal. A needle cap stem is upstanding from the base and sized and configured to insert through an opening is the housing proximal end to cover the needle tip when the syringe assembly is disposed in the first position. The needle cap base further includes a plurality of distally projecting cams located radially outward of the stem. The cams are fittable within slots in the housing proximal end when the cap is fully mounted to the apparatus.